U.S. patent number 5,710,567 [Application Number 08/590,911] was granted by the patent office on 1998-01-20 for antenna locking device using magnetic attractive elements when antenna is extended.
This patent grant is currently assigned to Allgon AB. Invention is credited to Magnus Funke.
United States Patent |
5,710,567 |
Funke |
January 20, 1998 |
Antenna locking device using magnetic attractive elements when
antenna is extended
Abstract
An antenna device for a piece of equipment for transmitting
and/or receiving radio signals, wherein the antenna device
comprises a first extendable antenna (2), which is movable between
an extended position, where it is coupled to the circuitry of the
piece of equipment and a retracted position where it is not coupled
to the circuitry, the extendable antenna (2) on its lower portion
having first holding device (10) cooperating with a second holding
device (9) arranged on a guide (5) for the first antenna such that
the first antenna is releasably locked in the extended position.
According to the invention the first antenna (2) is releasably
locked by the first and second holding devices comprising mutually
magnetically attractive elements (9,10).
Inventors: |
Funke; Magnus (.ANG.kersberga,
SE) |
Assignee: |
Allgon AB (Akersberga,
SE)
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Family
ID: |
20399959 |
Appl.
No.: |
08/590,911 |
Filed: |
January 24, 1996 |
Foreign Application Priority Data
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Oct 25, 1995 [SE] |
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9503758 |
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Current U.S.
Class: |
343/702; 343/725;
343/901; 343/900 |
Current CPC
Class: |
H04B
1/3833 (20130101); H01Q 1/244 (20130101) |
Current International
Class: |
H01Q
11/08 (20060101); H01Q 1/12 (20060101); H01Q
11/00 (20060101); H01Q 1/24 (20060101); H01Q
1/10 (20060101); H01Q 1/08 (20060101); H01Q
001/24 () |
Field of
Search: |
;343/702,900,901,903,877,787,725,729 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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0467822A2 |
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Jan 1992 |
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EP |
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0516490A2 |
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Dec 1992 |
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EP |
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WO94/10720 |
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May 1994 |
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WO |
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Primary Examiner: Wimer; Michael C.
Attorney, Agent or Firm: Jacobson, Price, Holman &
Stern, PLLC
Claims
I claim:
1. An antenna device for a piece of equipment for transmitting
and/or receiving radio signals, said antenna device comprising a
first extendable antenna which is movable between an extended
position where the first extendable antenna is coupled to circuitry
of the piece of equipment and a retracted position where the first
extendable antenna is essentially not coupled to said circuitry,
said extendable antenna having a lower portion equipped with first
holding means for cooperating with second holding means arranged on
a guide means for holding the extendable antenna such that the
extendable antenna is releasably locked in the extended position,
wherein the extendable antenna is releasably locked by magnetic
attraction between the first and second holding means, said first
and second holding means comprising mutually magnetically
attractive elements.
2. The device according to claim 1, wherein the first and the
second holding means comprise abutting surfaces which contact each
other in and define said extendable position.
3. The device according to claim 1, wherein said first and second
holding means are arranged to couple the extendable antenna
galvanically to said circuitry.
4. The device according to claim 1, wherein said first and second
holding means are arranged to couple the extendable antenna
capacitively to said circuitry.
5. The device according to claim 1, wherein the second holding
means comprises a magnet.
6. The device according to claim 5, wherein the second holding
means comprises an annular magnet surrounding the extendable
antenna.
7. An antenna device for a piece of equipment for transmitting
and/or receiving radio signals, said antenna device comprising a
first extendable antenna which is movable between an extended
position where the first extendable antenna is coupled to the
circuitry of the piece of equipment and a retracted position where
the first extendable antenna is essentially not coupled to said
circuitry, said extendable antenna having a lower portion equipped
with first holding means for cooperating with second holding means
arranged on a guide means for holding the extendable antenna such
that the extendable antenna is releasably locked in the extended
position by magnetic attraction between the first and second
holding means, said first and second holding means comprising
mutually magnetically attractive elements and wherein at least one
of the first and the second holding means includes a magnet.
8. The device according to claim 7, including a second antenna,
which is constantly coupled to said circuitry.
9. The device according to claim 8, wherein said second antenna is
a helical antenna.
10. The device according to claim 9, wherein the helical antenna is
arranged so as to surround a movement path of the extendable
antenna and wherein said guide means is arranged on or in a casing
or a support body for the helical antenna.
11. The device according to claim 8, wherein said second antenna is
a patch antenna.
12. A piece of equipment for transmitting and/or receiving radio
signals including an antenna device comprising an extendable
antenna which is movable between an extended position where the
extendable antenna is coupled to the circuitry of the piece of
equipment and a retracted position where the extendable antenna is
essentially not coupled to said circuitry, said extendable antenna
having a lower portion equipped with first holding means for
cooperating with second holding means arranged on a guide means for
holding the extendable antenna such that the extendable antenna is
releasably locked in the extended position by magnetic attraction
between the first and second holding means, said first and second
holding means comprising mutually magnetically attractive elements
and wherein at least one of the first and the second holding means
includes a magnet.
13. The piece of equipment according to claim 12, wherein the first
and the second holding means comprise abutting surfaces which
contact each other in and define said extended position.
14. The piece of equipment according to claim 12, wherein said
first and second holding means are arranged to couple the
extendable antenna galvanically to said circuitry.
15. The piece of equipment according to claim 12, wherein said
first and second holding means are arranged to couple the
extendable antenna capacitively to said circuitry.
16. The piece of equipment according to claim 12, including a
second antenna, which is constantly coupled to said circuitry.
17. The piece of equipment according to claim 16, wherein said
second antenna is a helical antenna.
18. The piece of equipment according to claim 17, wherein the
helical antenna is arranged so as to surround a movement path of
the extendable antenna and wherein said guide means is arranged on
or in a casing or a support body for the helical antenna.
19. The piece of equipment according to claim 15, wherein said
second antenna is a patch antenna.
Description
BACKGROUND OF THE INVENTION
This invention concerns an antenna device for a portable piece of
equipment for transmitting and/or receiving radio signals, said
antenna device comprising a extendable antenna, which is movable
between an extended position, where it is coupled to the circuitry
of the piece of equipment and a retracted position where it is
essentially not coupled to said circuitry, said extendable antenna
on its lower portion having first holding means cooperating with
second holding means which is arranged on a guide means for the
extendable antenna such that the extendable antenna is releasably
locked in the extended position.
WO 94/10720 describes antennas for mobile telephones including in
combination a helical antenna arranged outside of the main body of
a mobile telephone, an extendable rod antenna and an impedance
transformer. According to this publication switching is achieved by
extending and retracting the rod antenna. In the retracted position
the rod antenna is neither galvanically nor capacitively coupled to
the impedance transformer. In this position the antenna function
thus consists of only the helical antenna which is constantly
coupled to the impedance transformer. In the extended position the
helical antenna and the rod antenna are connected in parallel to
the impedance transformer. Coupling is possible to obtain with
either galvanical or non-galvanical coupling of RF-signals, e.g.
between the rod antenna and the helical antenna/the impedance
transformer or between the helical antenna/the rod antenna and the
impedance transformer.
The coupling and decoupling of the rod antenna is thus effected by
extending and retracting the antenna rod. The extension thereof is
limited by the lower part of the rod antenna being stopped by a
contact part and a sleeve. The contact parts also serve as a
mechanical locking mechanism for the antenna rod in its extended
position. According to another example, when the coupling is
capacitive, one of the meeting elements may be provided with a thin
insulating layer.
The mechanical locking of the mutually movable parts, however,
brings about demands of high precision in manufacture with respect
to the co-operating elements. Because of these demands and the fact
that the solution presupposes the assembling of a number of
elements the production costs are relatively high.
SUMMARY OF THE INVENTION
It is an aim of this invention to overcome the above mentioned
disadvantages and to suggest an antenna device which may be
produced at a low price and which provides a distinct locking in
the extended position of the extendable antenna, repetitively with
the same locking force.
This aim is achieved in an antenna device according to the above by
the extendable antenna being releasably locked by the first and
second holding means comprising mutually magnetically attractive
elements.
By providing the locking function magnetically there is no need for
a particularly high precision between contacting parts in order to
achieve a sufficient locking force, since the co-operating holding
means may be manufactured with play with respect to each other.
Further, a distinct stop is obtained in the extended position which
facilitates obtaining of the position in which the antenna is fully
extended and indicates to the user when full extension of the
antenna is achieved. Another important advantage is that
practically no wear occurs between the mutually moving parts in the
device according to the invention irrespective of axial or even
rotating movements of the antenna. In case of capacitive coupling
of the extendable antenna in its extended position the solution
according to the invention enhances the antenna function since such
a coupling is relatively dependent on correct orientation of the
coupling parts. This advantage is further enhanced by the first and
the second holding means comprising abutting surfaces which contact
each other in and define said extended position.
By first and second holding means being arranged to couple the
extendable antenna galvanically to said circuitry a reliable and
efficient function for the antenna device is guaranteed.
By the second holding means comprising a magnet and in particular
said magnet being annular and surrounding the rod antenna,
sufficient locking force is easily obtained with a relatively small
magnet and the magnet may be located such that the influences on
the antenna function are minimized.
The additional feature that the first holding means includes a
magnet brings about an easily produced and economical solution.
This invention is particularly advantageous if it also includes a
second antenna. This solution is particularly useful in connection
with portable telephones or similar pieces of equipment.
The feature that the second antenna is a helical antenna and more
in particular wherein the helical antenna is arranged so as to
surround the movement path of the extendable antenna and said guide
means being arranged on or in the casing or the support body for
the helical antenna brings about a compact and easily manufactured
antenna device.
This invention also concerns a piece of equipment for transmitting
and/or receiving radio signals including a device according to the
above.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described in greater detail at the
background of an embodiment and with reference to the annexed
drawings, wherein:
FIG. 1 shows, partly in section, an embodiment of the invention
with the first antenna in its extended position, and
FIG. 2 shows the device according to FIG. 1 with the first antenna
in the retracted position.
DESCRIPTION OF A PREFERRED EMBODIMENT
The dual antenna device 1 in FIG. 1 comprises a first antenna 2 in
its extended position. In the embodiment, the first antenna is
comprised of a rod antenna but it may be any other extendable
antenna. A second antenna 3 is helically coiled on a support
structure 4 and placed inside a casing 5. The first antenna 2 is
thus movable inside the second helical antenna 3 between the
extended position (FIG. 1) and the retracted position (see FIG. 2).
At its upper portion the first antenna is provided with an upper
part 7 of insulating material so as to avoid influencing the
helical antenna 3 when the first antenna 2 is in the retracted
position. At its uppermost end the first antenna 2 is provided with
a gripping knob 6.
In its lowermost region the first antenna 2 is provided with a
stopper element 10, which constitutes the first holding means. The
casing 5 is at its bottom region provided with a seat for an
annular magnet 9 which constitutes the second holding means and is
placed such that it surrounds the first antenna. The magnet 9 is
provided with a radially outwards open slot 9' for a connector wire
8 which is intended for connection between the two antennas and the
circuitry of the piece of equipment. The connector wire 8 is placed
in such a way within the slot 9' that galvanic contact with the
magnet 9 is obtained.
FIG. 2 shows the dual antenna device 1 with the first antenna 2 in
the retracted position. In this figure a first abutting surface 11
is shown on a radially extending shoulder on the stopper element.
This abutting surface 11 contacts a corresponding second abutting
surface 12 in the region of the magnet 9 when in the extended
position. In the embodiment shown this second abutting surface is
constituted by a collar surface on the magnet itself but it may be
constituted for example by the surface of an annular washer, a part
of the casing etc. In case of galvanic coupling of the first
antenna it is essential that metallic contact is safely obtained
between the two abutting surfaces and the contact function may be
enhanced by using a washer of a suitable material.
The first antenna is locked in the extended position by means of
magnetic attraction between the magnet 9 and the stopper element
10. Preferably the distribution of material in the stopper element
10 and the magnet 9 is such that the magnetic attraction force
forces the surfaces 11 and 12 against each other in order to obtain
a defined extended position and guarantee the galvanic
coupling.
Although the invention has been described in connection with one
particular embodiment it is emphasized that the scope of the claims
allow also other embodiments.
The coupling between the antenna device according to the described
embodiment and the circuitry of the piece of equipment, onto which
it is attached, is such that the second, helical antenna is coupled
alone (or at least mainly) to said circuitry when the first antenna
is in the retracted position, whereas the first and the second
antennas are coupled in parallel to said circuitry when the first
antenna is in the extended position.
It is possible to use other types of extendable antennas also when
not co-operating with or being in the direct neighborhood of a
second antenna. The scope of this invention thus includes antenna
devices having only an extendable antenna and devices where the
extendable antenna is arranged separately with respect to and at a
distance from a second antenna. Said second antenna may be a
helical antenna, a patch antenna or any other suitable antenna. In
cases where the path of the extendable antenna is not surrounded by
the casing or the support body for a helical antenna, guide means
for guiding the movement of said extendable antenna may be provided
on a separate body or casing or may be arranged on or inside the
housing of the piece of equipment onto which it is attached.
The arrangement of the first and second holding means may be
inverse such that the first holding means contain the magnet
whereas the second holding means comprise magnetically attractive
material. Also the use of a magnet in both the first and the second
holding means is possible.
The magnet may have another form although the annular form is
preferred because it allows a slim construction and sufficient
intensity of magnetic field. It is thus possible to use a magnet or
magnets not surrounding the extendable antenna or separate magnetic
elements arranged in a distributed manner around the path of the
extendable antenna. Coupling between the magnet and the wire 8 may
be achieved in several different ways. According to another
solution the magnet is annular but manufactured without the slot 9'
and the wire is pressed between the outside of the magnet and the
magnet seat of the casing.
Different materials may be used for the elements 9 and 10 but it
could be mentioned that neodym-material is preferred in the magnet
since the intensity of magnetic field per volume unit using such
material allows the use of a small and flat magnet which
constitutes less restrictions for the antenna length.
It is also desirable to lock the first antenna in the retracted
position, and this may be achieved according to the shown
embodiment by means of a groove 13 immediately below the knob 6
co-operating with the inward flange portion 14 at the upper guiding
hole of the casing 5. A possible development of the antenna is to
arrange a magnetic material inside the upper part 7, which element
co-operates with the magnet 9 in the retracted position. Another
solution is to have the first holding means co-operating with a
separate magnet (or vice versa) inside the casing of a piece of
equipment such as a portable telephone.
It could be mentioned that in a preferred method of fixing the
upper part 7 onto the rest of the first antenna, the upper part is
provided with a hole 15 at its lower end which matches onto an
extending free and uncovered portion 16 of the first antenna 2.
Appropriate fixing is obtained by gluing, possibly enhanced by
providing the portion 16 with engagement protrusions or notches. An
embodiment where the knob 6 is placed more closely to the free end
of the antenna rod 2 which thus at least partly is positioned
inside the helix also in its retracted position (compare with FIG.
2, where the rod is below the helix) is also possible in spite of
influences on the function of the helix antenna because of the
possibility of having a particularly short rod antenna and/or
enhanced rod antenna function.
In order to easily attach the casing and thereby the antenna device
to a portable telephone or the like, it is desirable that the
casing 5 is resilient and is provided with an annular groove 17 at
its lower part in order to allow snap-in fixing in a corresponding
hole in the housing of the piece of equipment.
* * * * *